Astronomers are on the Hunt for Dyson Spheres

https://lemmy.world/post/15298187

Astronomers are on the Hunt for Dyson Spheres - Lemmy.World

A Ringworld would be more likely than a Dyson sphere, the mass requirements are so much lower.
But it’s unstable.
If a civilization can figure out how to make one, they can keep it from sliding into the sun!
Like how if they figure out how to build an 833’ long ship they can keep it from immediately hitting an iceberg and sinking?
Or the most advanced starship in the galaxy not having a Spontaneous Massive Existence Failure
You know, that’s a really good point, but this is on such a bigger scale and if it’s a known problem today, I think they would know about it by the time they can build something like that.
Damn, imagine the number of lifeboats you’d need to evacuate a Dyson Sphere?
Just glue 3 of them together, that’ll make them 300% stable!
220, 221. Whatever it takes!
So is a Dyson sphere?
Spheres aren’t unstable around a star. Rings are unstable in orbit around a star.
what’s ringworld?

en.m.wikipedia.org/wiki/Ringworld_series

Imagine a slice of a Dyson sphere, about one earth wide and one earth deep.

Ringworld series - Wikipedia

Or the halo from the game 'halo'
Though its important to note that the halos aren’t true ringworlds, they aren’t nearly big enough.
I guess the big difference is it doesn't encircle the sun
Basically. The the whole idea is that it’s 1 AU out so it’s in the habitable zone, spinning fast enough to simulate 1 gravity. Stats for nerds.
Ringworld parameters

Parameters and technical specifications for Larry Niven's Ringworld.

Also known as a Banks orbital.
The Culture - Wikipedia

Yeah. Ringworld was written way before that and Dyson thought it was a cool idea. Glad to see it used in other stories.
Wouldn't a Dyson swarm be much easier to construct than either? Like a dyson sphere but a swarm of smaller collectors.
A swam doesn’t produce anywhere near the real estate though. So I guess it really depends entirely on why the megastructure was built, if it’s only for energy extraction then yeah, a Dyson swarm makes the most sense. But if they also want to use it for habitation then it’s not a really great idea. Sure you can spread space station’s throughout the swarm, but then groups in space station A are always going to find it difficult to interact with groups in space station B, no matter how commonplace space travel is. It would be like intentionally building two cities on either side of a canyon, and saying it’s okay because aircraft exist.
RTFA they are looking for swarms, rings, and other subtypes of Dyson Spheres.
I read the fucking article. What makes you fucking think I didn’t?
The fact that you just reiterated one of its points.
Huh. So commenting on the content of the article means it wasn’t read? That’s a really odd position to take.
Ringworlds are not orbitally stable so they are firmly in the realm of sci fi.
Neither are Dyson spears
Got mine plugged in: gonna vacuum later
Ha ha yup me too! Got one hiding in my closet. $50 and it’s theirs 🤣
Isn't that like a 95% loss?
From MSRP, yes. Mine was second hand and has seen better days. One of the older DC07 ones

Okay, so the title is a bit off. They’re hunting for partial Dyson spheres using infrared and optical.

I was confused on how they would detect something completely blocking a sun from millions of light-years away.

Dyson swarms are more likely. We even have a tiny one with our satellites using solar power in a heliocentric orbit. (Dyson spheres are basically impossible.) But we could theoretically detect either in infrared since if it doesn’t give off waste heat, it’d all heat up and melt.

That being said, I’m personally of the opinion this is a waste of time. Not to get all Fermi Paradox but it’s pretty sci fi brained to think any other species out there is as dumb as we are. Space sucks. You die super fast there. Everything had to align just right for Earth to make a bunch of dumb fuck apes willing to strap themselves onto rockets, have a planet small enough that the rocket could even enter orbit using chemical rockets, and a World War and Cold War to accelerate things.

Time will always be the great filter. Even if we did spot a Dyson swarm, we have no feasible way to contact anything on a practice timescale. Any speck of civilization we detect will be hundreds of thousands of years out of date at best, billions at worst. Life in the universe, imo, is basically guaranteed. If it happened once, it can happen again. Meaningful contact between separately evolved concurrent sapient species? Not likely.

Everything had to align just right for Earth to make a bunch of dumb fuck apes willing to strap themselves onto rockets, have a planet small enough that the rocket could even overcome gravity to enter orbit using chemical rockets, and a World War and Cold War to accelerate things.

Given the estimated number of planets in this galaxy alone, it’s particularly guaranteed that very similar events have occurred on multiple worlds. Unless you’re proposing that all theoretical alien races are Vulcan level logical then tensions and interstate conflicts will always exist that will advance technology. This is practically an inevitability in less the racing question is a hive mind species.

I think my Fermi Paradox explanation isn’t that space is really fucking big and hostile and protecting the planet you evolved on is the only real option.

Not to mention the problem of what life is even supposed to do beyond a certain point of development. The depressing fact is that there is a finite amount of knowledge to be gained, a finite amount of resources to harvest, a finite diversity of life to contend or thrive alongside with. Once a pocket of life in this massive universe begins to run out of things to do and stagnates, then what? What is there to think about; to feel; to experience?

There’s little point in exploring space if one know how this universe works. One knows the rules, knows all the ways it can play out, and there’s no surprise waiting on the other end of any venture one can imagine embarking on.

That’s my theory. The Great Filter is just depressive boredom. We don’t see other life because by the time a civilisation is able and ready to spend thousands of years travelling through deep space, they’ll have already lost any motivation they might have had to do so.

I suspect that there’s at best a very short window wherein a species is both knowledgeable enough to dream of space exploration and technologically capable of sending any significant amount of artificial constructions out there.

Not to mention that anything an alien species might send into interstellar space is unimaginably unlikely to be recorded exactly at precisely the moment they pass another lump of matter - especially if the window is as short as I fear.

Even a Dyson sphere, which is technically unlikely anyway, would be possible to spot. You would look for something very bright in the infrared spectrum with almost no light in the visible spectrum. It would also be larger than a normal star of the same energy, but that would be hard to tell given all the other issues.

A partial swarm is easier because it will have variability towards more infrared and then back to a more normal spectrum.

And, of course, all this is speculation until we find a candidate and determine it doesn’t have a natural source for that behavior.

Why would there necessarily be strong infrared emissions? Since a Dyson Sphere is meant to harvest all energy produced by a star, any leakage would be unnecessary inefficiency, wouldn’t it?

Because all that energy contains heat as well, and you’ll need to balance the heat from your star along with the energy absorbed.

You’re never going to get to 100% efficient conversion, so you’ll have to radiate away the heat so your sphere doesn’t melt or something.

Sure, you won’t reach 100%. But say you reach 99.9% - the Dyson sphere should radiate infrared at 0.1% of a normal star, right? It wouldn’t necessarily be bright.
They must be mining a lot of bitcoin to need 99.9% of a star’s energy.
Maybe they are just fabricating matter. That takes a surprising amount of energy!
Even if that level of efficiency were possible, 0.01% of a star’s output is still a substantial amount of heat.

Yeah, it’s interesting to think about IR powered thrust.

I wonder if moving a star by cooling one side could ever happen? Like in a some weird future tech way obviously.

Not all heat can be converted to work by the second law of thermodynamics. Now the question is, how hot can the star be for it to sustain life? Can most of its light be UV with very little visible? …lumenlearning.com/…/15-4-carnots-perfect-heat-en…
Carnot’s Perfect Heat Engine: The Second Law of Thermodynamics Restated | Physics

Thermodynamics says that energy can’t be destroyed (mass-energy, but generally that won’t matter). So after the work of running your stellar civilization is done, you will radiate out waste heat. There is no real way around this without breaking thermodynamics or having a handy black hole to dump all your waste heat into. Therefore, the energy of the star will still be released, but it will be released as infrared.

If you’re using the Dyson sphere purely as a power plant and e.g. charge batteries, the thermal radiation will be distributed over the whole area covered by the civilization.

A solar panel, or any other power generator we use, doesn’t radiate away all the generated energy either. It’s radiated from the point of use.

So you heat habitats, which radiate heat. And run computers, which radiate heat. And move objects around, which radiates heat (among other things). And if you merely absorb energy from your star…it radiates as heat. This is the whole idea of entropy. Unless your lasers are particularly efficient and you use them to beam the energy elsewhere, your Dyson swarm is going to radiate heat equivalent to the energy your star puts out.
You’re ignoring my example - what if you charge up batteries at the Dyson sphere, and use the energy anywhere else? There’s no physical reason the energy must be used around the Dyson sphere.
So all you need is a perfect charging system. We don’t have those, and physics doesn’t allow for them. This would be no different than the laser example I gave, and this only makes sense after you have a second Dyson swarm.
Why perfect? As long as the efficiency is high enough, you wouldn’t see the sphere itself as very bright, it would be quite dim. Do we know any hard, physical limitations for this, like we do for speed?

I don’t think you have any appreciation for just how much energy even a dim star provides. A Kardashev 2 civilization has access to a billion times the energy we (Earth) have, and we only use about 70% of the energy we have access to. Even if you use all that energy, there will still be waste heat. Now you’re proposing that this hypothetical civilization has a second star (at least) that it’s importing energy from, which means it will be a larger area emitting infrared in their home system, because thermodynamics still has to be obeyed.

And yes, the laws of thermodynamics have to be obeyed. They are as rigid as the speed of light, meaning there might be shortcuts but they are very advanced. To put it in perspective, we are almost capable of starting a Dyson swarm, and we have no options for bypassing the laws of thermodynamics and only have the barest ideas of how to bypass the speed of light.

I don’t think you have any appreciation for just how much energy even a dim star provides. A Kardashev 2 civilization has access to a billion times the energy we (Earth) have, and we only use about 70% of the energy we have access to.

We also have no idea what such large amounts of energy could be practically used for. Just as one possible example, the recent approach for warp drives would consume large amounts of energy - and it would cause the energy to be used over a large area, going against your assumptions. Of course there are many other options, e.g. creating matter from energy.

Even if you use all that energy, there will still be waste heat.

Yes, and as I keep repeating, the waste heat would not necessarily be produced at the location of the Dyson sphere.

Now you’re proposing that this hypothetical civilization has a second star (at least) that it’s importing energy from, which means it will be a larger area emitting infrared in their home system, because thermodynamics still has to be obeyed.

First: why must there necessarily be a second star? They could live inside ships in-between solar systems, which would only need one star to import energy from, and no more. And my whole point is that this would make the Dyson sphere itself much dimmer than you’re assuming it to necessarily be.

And yes, the laws of thermodynamics have to be obeyed. They are as rigid as the speed of light, meaning there might be shortcuts but they are very advanced. To put it in perspective, we are almost capable of starting a Dyson swarm, and we have no options for bypassing the laws of thermodynamics and only have the barest ideas of how to bypass the speed of light

You haven’t shown that the laws of thermodynamics actually pose limits here. Nothing I’m proposing goes against the laws of thermodynamics.

'Warp drives' may actually be possible someday, new study suggests

"By demonstrating a first-of-its-kind model, we've shown that warp drives might not be relegated to science fiction."

Space

Sorry, all I’m seeing are reasons how you could take all the energy from a given star and move it elsewhere without a reason to do so, even to the point where virtually none of that energy is being used locally. This is the classic solution looking for a problem idea.

There are plenty of resources on the internet that have already responded to all your questions. Feel free to look it up.

Yes, I was only focusing on the “physically possible” part. I don’t think it makes sense for us to inherently limit our search for such things to the most obvious solution - focus on that first, sure, but don’t rule out that non-physically based assumptions are wrong. We can’t assume that a civilization capable of producing a Dyson sphere would exactly follow what we assume to make the most sense.

But I can gladly provide some possible reasons:

  • A dark forest scenario would mean that you’d want to hide your energy harvesting as much as possible, while also not living close to megastructures that could be discovered from afar
  • A civilization focused on exploring surrounding star systems would automatically spread their energy usage around a wide area
  • They could be building things they don’t want lower civilizations to see (e.g. prime directive), which would necessitate building them in voids (as long as they don’t have technology to cloak it)

You’re writing as if the assumption of local energy usage is physically given and can’t be wrong, but we simply can’t know for now. It could be right, or it could be wrong. Again, I agree that it makes sense to assume it to be correct, as it would be a much more easily recognizable marker, but that doesn’t mean it’s the only option.